Metal protective hoses of this type are also referred to as conduits in installation technology. These metal protective hoses or conduits, because of corresponding standards, are used in Anglo-Saxon and Asiatic countries, especially in Great Britain, North America and Canada. These conduits can be designed both as metal tubes and as plastics material tubes or metal hoses or plastics material hoses. A metal hose designed in the manner of a corrugated tube is used particularly frequently as a conduit. A metal profile is often coiled to form a hose, such that the finished metal hose has a coiled thread-like outer sheath. Electrical lines, for example for installation in buildings, are introduced into the metal hoses or conduits. These electrical lines then lie well protected in the conduits and are laid in the cable ducts of buildings. The earthing of the conduit with its electrical lines then also takes place by means of the cable ducts.
A protective hose of this type is known, for example, from the European patent stemming from the applicant having the publication number EP 2 499 705 and the title “ELECTRICAL PLUG CONNECTOR”. In this case, the metal protective hose is connected indirectly to the earthing line. Disclosed therein are, specifically, a comb-like and a fork-like earthing contact, which rest with the comb prongs or fork prongs on the metal hose and, at the end thereof remote from the metal hose, in each case have a contact lug, which can be contacted with the aid of a cable shoe or the like. The earthing contact is, so to speak, interposed between the metal hose and the actual earthing line.
A further solution also stems from the applicant and is the subject of the German utility model having the reference number 20 2015 106 155.2 and the title “FASTENING DEVICE”. This solution is based on the basic idea of directly contacting the outer sheath of the protective hose. For this, the end of the earthing line is designed as an earthing contact. In this case, the end of the earthing line is connected, preferably screwed, by means of a contact part to the outer sheath of the corrugated tube.